FAQ Guide – Hydrogen Pressure Solenoid Valve
- What is a hydrogen pressure solenoid valve?
- What is the working principle of a hydrogen pressure solenoid valve?
- What are the application areas of these valves?
- Which pressure ranges are covered by pressure solenoid valves in the hydrogen economy?
- What are the performance criteria of the hydrogen pressure solenoid valve?
- What are the major technical parameters required for using these valves?
- Are the materials used for hydrogen pressure solenoid valves important?
- What testing conditions and procedures are used to produce hydrogen pressure solenoid valves for example hydrogen refueling station?
- What are the safety parameters/precautions related to hydrogen pressure solenoid valves?
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What is a hydrogen pressure solenoid valve?
A hydrogen pressure solenoid valve is an electromechanically operated device which is used to control the flow of hydrogen gas. The solenoid generates a magnetic field that moves a plunger inside the valve, which opens or closes the valve allowing hydrogen to flow through or blocking it. The solenoid valve has a compact design and is commonly used in systems that require precise control of the flow of fluid. They are generally used for applications that require, fast and safe switching, low energy consumption, high reliability, and good medium compatibility. Therefore, it makes them ideal for hydrogen-based industrial and automotive applications.
What is the working principle of a hydrogen pressure solenoid valve?
There are two main types of working principles commonly used for hydrogen applications, direct-acting and pilot-operated. The main difference between direct-acting and pilot solenoids is that pilot-operated valves employ the use of the process fluid to assist in the opening and the closing of the valve along with the magnetic field, whereas direct-acting valves rely only on the magnetic force from the solenoid to open or closed the orifice.
- Direct acting: A direct-acting solenoid valve generates an electromagnetic force by passing an electric current through a solenoid coil. The solenoid coil is wound around a movable plunger within the valve. When an electric current passes through the solenoid coil, the solenoid valve is activated, and a magnetic field is created that pulls a piston or plunger into the solenoid. The plunger’s movement opens or closes the valve, allowing or preventing the flow of hydrogen gas through the valve. A spring returns the valve to its original position when the solenoid is de-energized.
- Pilot operated: Unlike a direct-acting solenoid valve, a pilot-operated solenoid valve, controls the flow of fluid through the main valve by using a small auxiliary valve (the “pilot valve”). When the solenoid is activated, it opens the pilot valve, allowing a little amount of fluid to enter the main valve. This causes the change in system line pressure which opens the primary valve, allowing fluid to flow through. When the solenoid is de-energized, the pilot valve closes, causing the main valve to close and cease the flow of fluid.
What are the application areas of these valves?
Hydrogen gas pressure solenoid valves are used in a wide range of industrial and automotive applications. It is mainly used where precise control over the flow of a fluid (liquid or gas) is required. One common application area of these valves is in hydrogen refueling stations, where valves are installed to allow or stop the flow of hydrogen. They are also used in various industrial applications, such as in chemical and petrochemical plants, power generation, food and beverage processing, automotive, aerospace, and medical equipment to regulate the flow of water, air, gas, and oil.
Which pressure ranges are covered by pressure solenoid valves in the hydrogen economy?
Generally, hydrogen solenoid valves are used in two main pressure categories: 500 bar and 1000 bar. These ranges are chosen based on the pressure requirements of the specific application. Generally, this means that the direct-acting valves can work from 0 bar up to 1000 bar, while the pilot-operated valves can work from 10 bar up to 1000 bar. It is also important to note that the pressure range will vary depending on the specific valve design and the materials used in its construction. Therefore, it is essential to select the appropriate valve for the specific pressure range and application requirements.
Pressure solenoid valves in the hydrogen economy typically operate in the range of 0-10,000 psi (0-700 bar). The exact pressure range will depend on the specific application and the requirements of the system in which the valve is being used.
What are the performance criteria of the hydrogen pressure solenoid valve?
The performance criteria of a hydrogen gas pressure solenoid valve vary depending on the specific application and requirements. However, there are six key performance indicators (KPIs) that are commonly used to evaluate the performance of these valves.
- Orifice size: The size of the valve opening that controls the flow of hydrogen, typically measured in millimetres or inches.
- Maximum allowable working pressure: The highest pressure the valve can withstand while still maintaining a safe and reliable operation.
- Mass flow coefficient: A measure of the valve’s ability to control the flow of hydrogen.
- Pressure drop: The difference in pressure between the inlet and outlet of the valve, measured in bars or pounds per square inch.
- Internal and external valve leakage: The amount of hydrogen that leaks through the valve, measured in cubic centimetres per minute or cubic feet per hour.
- Lifetime (number of cycles): The number of times the valve can be opened and closed before it needs to be replaced, typically measured in millions of cycles.
The above-mentioned KPIs are used to evaluate the performance of a hydrogen pressure solenoid valve, and this ensures that the valve meets the requirements of the specific application. The specific application will dictate which KPI will be more important to focus on.
What are the major technical parameters required for using these valves?
When using high-pressure hydrogen solenoid valves, seven technical parameters are required to ensure that the valve is appropriate for the specific application and that it will perform as intended.
- Type of fluid to be controlled: The type of fluid, whether it is a liquid or gas, and its properties, such as viscosity and density, will affect the performance of the valve.
- Temperature range of fluid: The range of temperatures at which the fluid will be flowing through the valve, as this can affect the valve’s performance and durability.
- Temperature range of environment: The range of temperatures in the environment in which the valve will be installed, as this can also affect the valve’s performance and durability.
- Minimum and maximum flow required: The range of flow rates that the valve will need to handle.
- Minimum and maximum inlet pressure: The range of inlet pressures that the valve will need to handle.
- Minimum and maximum outlet pressure: The range of outlet pressures that the valve will need to maintain.
- Inlet and outlet pipeline size: The size of the inlet and outlet pipelines, as it will affect the flow rate and pressure drop through the valve.
Are the materials used for hydrogen pressure solenoid valves important?
The materials used for hydrogen pressure solenoid valves are important because hydrogen gas poses two specific difficulties. Due to its small size, hydrogen can diffuse rapidly into or through most materials, which can cause leaks or other problems. Hydrogen is also known to affect some materials by increasing their brittleness, a phenomenon known as hydrogen embrittlement. This can cause the valve to become fragile and more prone to failure.
Therefore, the choice of metal and polymer used for the valve construction is highly important. The valve body and other components must be made of materials that are resistant to hydrogen diffusion and hydrogen embrittlement. Stainless steel, titanium, and other corrosion-resistant metals are often used for the valve body and other components. Additionally, the polymer used in the valve construction must be approved against explosive decompression.
It is also important to note that the materials used for hydrogen pressure solenoid valves must also meet other requirements, such as high-pressure resistance, temperature resistance and corrosion resistance. The valve should be able to withstand the conditions of the application, both in terms of pressure, temperature, and chemical exposure.
What testing conditions and procedures are used to produce hydrogen pressure solenoid valves for example hydrogen refueling station?
When producing high pressure hydrogen solenoid valves for hydrogen applications, various testing conditions and procedures are used to ensure that the valves meet the required specifications and will perform as intended. The hydrogen valve shall be tested according to the latest release of ISO 19880-3. This standard specifies the testing procedures and acceptance criteria for high-pressure valves used in hydrogen systems.
The standard covers various aspects of valve performance, including pressure and leak testing, flow testing, and endurance testing. Pressure testing is done to ensure that the valve can withstand the maximum allowable working pressure without any leakage or damage. The leak testing is done to check for any internal or external leakage of hydrogen. Flow testing is done to check if the valve can control the flow of hydrogen according to the specified flow rate. Endurance testing is done to check the life cycle of the valve.
In addition to these tests, the valves may also be subjected to environmental testing, such as vibration and temperature testing, to ensure that they can withstand the conditions of the intended application.
What are the safety parameters/precautions related to hydrogen pressure solenoid valves?
Hydrogen is a colourless and odourless gas that evaporates very easily and is also extremely flammable. Therefore, hydrogen valves shall comply with the ATEX directive 2014/34/EU for category 2 equipment. This directive sets safety requirements for equipment used in potentially explosive atmospheres, including hydrogen. The valves must be designed and manufactured to minimize the risk of ignition and prevent leaks.
Globally, IECEx in combination with country-specific directives certifies the use of components within hydrogen applications. The IECEx system provides certification of equipment and service facilities for use in explosive atmospheres, including hydrogen. In addition to compliance with these directives, it is important to ensure that the valves are installed and maintained according to the manufacturer’s instructions. This involves correct valve handling and storage, as well as frequent checks to ensure they are in good operating order. It is also critical to guarantee that the valves are only utilized for their intended purpose and that the individuals who operate the valves are properly trained and competent.
Content contributed by
SeitzValve is an independent, family-owned company with more than 60 years of experience. The core business of Eugen Seitz AG is solenoid valve technology for technically demanding applications. We develop solutions for gaseous media at medium to high pressure (16 to 1,000 bar). We are fully vertically integrated: All our products are developed, produced, packaged, and shipped from our head office in Switzerland in Wetzikon near Zurich. Our competitive offering is enabled by a high degree of automation – production runs 24/7 and with minimal manual input. Our industry-leading valves for hydrogen refueling station (HRS) applications enable ease of mind in refueling. We support H35 and H70 architectures with maximum fueling performance at low power, exceptional temperatures and with a minimal footprint. All valves are supplied with operating instructions and CoC (CE/PED, IECEx, ATEX, Nepsi, CCC and more). Availability and reliability are key differentiators of all Seitz valves. Every hydrogen valve is fully tested on an automated test bench for function and leakage with hydrogen forming gas. With our deep application engineering knowledge, we can integrate our premium solenoid valves in system modules, tailored to our customers’ needs. The SeitzValve team is ready for your challenges. Do not hesitate to contact us, we are happy to help you build a hydrogen economy.
Last update: 15.02.2023
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